Fruit Varieties and Horticultural Digest(J Fruit Var & Hort Digest)

Volume25Number4Article7Pages: 87-89
Year1971Month10Title: Pyrus Species and Pear Cultivar Germ Plasm Collection in OregonAuthors: M.N. Westwood, M.N. Thompson and P.B. LombardCitationAbstract:
A previous report (7) emphasized
that "single-clone specimen" Pyrus collections
in arboretums and botanic
gardens were generally unsuitable materials
for use in agriculture.
The
genus consists of about 22 species, all
of which are self-sterile, and thus require
more than one clone of a species
to obtain seedling populations for testing
which are not inter-specific hybrids.
Natural hybridization occurs
readily in this genus, so that controlled
crosses are needed for any plants used
in research.
During the past 10 years,
we have collected seeds from wild
Pyrus throughout the world, and have
established populations of each primary
species at Corvallis (Table 1).
Studies on rootstock potential, pest resistance
and inheritance characteristics
are underway (1, 2, 6, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17). Materials
were also made available to others for
a number of different studies (3, 4, 5,
in Table 2).
Besides the primary species collection,
we have a collection at Medford
of cultivars which includes 187 varieties
of P. communis, 6 of P. pyrifolia,
17 of P. ussuriensis and about 20 hybrids
of these species.
Many of these
show various degrees of resistance to
fire blight.